During operation of an internal combustion engine, fuel and lubricant deposits accumulate and bake onto the intake valves and intake ports of the fuel system. These deposits restrict the flow of air and fuel entering the combustion chamber which can cause stalling and hesitation, especially during "cold-start" operation.
Conventional polyalkenyl succinimides as gasoline detergent additives are described as effective in providing carburetor cleanliness and port fuel injector cleanliness. However, the polyalkenyl succinimides alone offer little intake valve cleanliness performance.